Expansion joint for floating roof sealing assembly



H. SMITH July 2, 1968 EXPANSION JOINT FOR FLOATING ROOF SEALING ASSEMBLYFiled March 22,

2 Sheets-Sheet 1 v INVENTOR HUBER? 5M! TH A TTORNE Y July 2, 1968 H.SMITH EXPANSION JOINT FOR FLOATING ROOF SEALING ASSEMBLY Filed March 22,1967 2 Sheets-Sheet 2 nwmron HUBER 7' 541/ TH BY ,M

V6? .2 Q9 ow If m mm em 5 -lri li uiil HlHi A Ta a '2 A fil L u luii- 2M k I f 1314:. n n. 4 a m k\ fl m h v a? N 5 m a? hall Ill|||| Q m bxk 5an RN mm 82 A TTORNE Y United States Patent Ofice 3,390,803 PatentedJuly 2, 1968 3,390,803 EXPANSION JOINT FOR FLOATING ROOF SEALINGASSEMBLY Hubert Smith, 601 Hinshaw Drive, Springdale, Ark. 72157 FiledMar. 22, 1967, Ser. No. 625,066 8 Claims. (Cl. 220-26) ABSTRACT OF THEDISCLOSURE A peripheral sealing assembly for a fluid storage tank havinga floating roof, including a multiple section shoe ring which embracesthe inner surface of the tank wall with the longitudinal extremtics ofthe sections of the ring in slidable overlapping relation. A multiplesection master seal strip extends from the upper portion of the shoering to the floating roof, and its longitudinal extremities arerelatively spaced adjacent the area of the overlapping portions of theshoe ring. A continuous expansion joint comprising a corrugated sealingweb bridges the spaced ends of the master seal and the overlappingportions of the shoe ring and is expandible and contractible in responseto relative sliding movement of the ends of the shoe ring sections.

Background of invention Conventional fluid storage tanks of the typeemploying a floating roof vapor seal are generally provided with anannular shoe ring seal formed of a plurality of arcuate plates whichcollectively embrace the inner wall of the tank in slidable relation,and are urged radially against the tank wall by suitable hangers whichare attached to the shoe ring and the floating roof and pushers whichare attached to the floating roof. At the junctions of the respectivesections or plates, expansion joints are provided to accommodate forrelative movement of the plates under expansion and contraction toaccommodate variations in tank shell circumference. The annular spacebetween the shoe ring and the floating roof is usually sealed by acontinuous strip of fabric or the like extending from the upper edge ofthe shoe ring to the rim of the floating roof.

These conventional structures have been found to be deficient inproviding adequate peripheral sealing because of the fact that in theareas where the shoe sections abut and the adjacent areas of thecontinuous peripheral sealing strip, there is no continuous expansionjoint to adequately accommodate for expansion and contraction in thearea from a point at or near the top of the shoe ring to the point ofconnection of the sealing strip to the floating roof. These structuresmust rely upon distortion, folds, stretching or slack in the materialused for the sealing strip to accommodate any circular or horizontalexpansion or movement of the shoe ring sections, which does not providefor adequate expansion in these areas.

Illustrative of a number of patents directed to this general field arePatents Nos. 1,574,013 to Wiggins and 1,931,551 to Larson.

Summary of invention The present invention overcomes these difficultiesby providing an expansion joint which extends continuously from at ornear the bottom of the shoe ring, upwardly to or near the top of theshoe ring, and then radially inwardly to the edge of the floating roof.The shoe ring of the invention is preferably formed of two or morearcuate sections or plates which, as in the case of prior shoe rings,.are maintained in slidable engagement with the inner surface of thetank shell. According to the invention, the terminal edges of respectiveplate sections are arranged in overlapping relation at the expansionjoint locations in order to provide for expansion and contraction, and amaster seal is attached to the upper portion of the shoe ring andextends radially inwardly where it is connected to the floating roof.The master seal, as in the case of the shoe ring, is formed of two ormore sections, each annularly spaced at its adjacent end from the nextsection, the spaces being arranged in the areas of the overlappingportions of the shoe ring sections.

Thus, the continuous expansion joint which is preferably formed of astrip of corrugated gas-tight material functions to accommodateexpansion at any point from at or near the bottom of the shoe ring, tothe top of the shoe ring, and thence to the connection of the masterseal to the floating roof. The opposite side edges of the expansionjoint web are connected in the respective areas to the oppositeoverlapping portions of the shoe ring sections and to the spaced edgesof the master seal sections and to the floating roof, which provides farmore freedom of movement in the expansion and contraction cycles of thecomplete peripheral sealing assembly and results in an improved shoe fitto the shell of the tank.

The drawings Referring to the dawings in which numerals of likecharacter designate similar parts throughout the several views:

FIG. 1 is a. fragmentary perspective view, partially in section,illustrating the upper portion of a storage tank with the floating roofand peripheral sealing assembly installed;

FIG. 2 is an enlarged sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken on line 33 of FIG. 2;

FIG. 4 is a similar view taken on line 44 of FIG. 3; and

FIG. 5 is a fragmentary sectional view taken on line 55 of FIG. 1,illustrating one form of hanger and pusher arrangement for supportingthe shoe ring assembly and maintaining sealing engagement of the shoering with the shell of the tank.-

Description of preferred embodiment Referring first to FIG. 1 of thedrawings, 10 represents a conventional cylindrical fluid storage tankhaving the usual floating roof 11, having a vertically extending annularwall 12 open at its upper extremity where it terminates in an inturnedflange 13. The floating roof and its wall 12 are inwardly spaced fromthe shell of the tank 10 by an annular clearance 14, and the purpose ofthis invention is to provide an improved peripheral sealing assembly forthis annular clearance.

This assembly includes a shoe ring generally indicated at 15, which ispreferably made up of at least two arcuate shoe ring sections 15a and15b, the meeting extremities of respective sections being arranged insliding, overlapping relation, as at 16, to accommodate relative slidingmovement of the sections during expansion or contraction of the shoering. A master seal 17 of flexible, gas-tight material is secured alongone longitudinal edge to the shoe ring 15 by means to be described, andoverlies the annular clearance 14 between the tank shell and thefloating roof, its opposite edge being connected to the flange 13 at theupper end of the floating roof wall 12.

This master seal is also formed in sections corresponding to the numberof sections in the shoe ring, and adjacent ends of the master sealsections are relatively spaced longitudinally as at 18 in the areas ofthe overlaps 16 of the shoe ring, as best seen in FIGS. 3 and 4. Thus,upon expansion and contraction of the shoe ring sections, the spacedends 18 of the master seal move correspondingly with the respectivesections so that the individual sections of the master seal are notdisturbed by bunching, stretching, or bulging.

The outer edge of the master seal is secured to the upper end of theshoe ring by a series of annularly spaced clamps 19, bolted or otherwisefastened as at 20. Preferably, the heads of the bolts are inset as at 21to facilitate the sliding engagement of the overlapping ends 15a and 15bof the shoe ring sections, as well as to permit a closer fit of the shoering to the tank shell. The opposite edge of the master seal is securedto the floating roof flange 13 by bolts 22 or other suitable means, asin FIG. 2.

In order to guide and control the relative sliding movement of theoverlapping ends of the shoe ring sections, the two clamping members 1%and 19]), adjacent the spaced extremities of the master seal in theoverlapping area of the shoe ring, are preferably in the formofhorizontal channel irons, designed to receive opposite ends of a controlbar 23, one end of which is fixedly secured within the channel 19a bybolt 24. The oppositeend of the control bar is slotted as at 25 andextends within the opposite channel iron 1%, a bolt 26 in the channeliron slidably engaging the slot 25. Thus, relative movement of theoverlapping ends of the shoe ring is directionally controlled andlimited in extent by the slot 25 and bolt 26.

One of the primary features of the invention resides in the provision ofan expansion joint for sealing both the overlapping ends of the shoering sections and the spaced ends of the master seal sections, adjacentthese overlapping areas. In the preferred form of the invention, thisexpansion joint comprises a continuous, corrugated web of flexible,gas-tight material, as shown at 27 in FIGS. 3 and 4. Opposite edges ofthis web are clamped directly to the inner surfaces of the shoe ringsections 15a and 15b by vertically disposed clamping bars 28 and 29respectively, secured by bolts or other suitable means 30, as best seenin FIGS. 2 and 3. The same opposite side edges of the corrugated web 27in the areas of the spaced ends of the master seal sections are securedto respective spaced ends by suitable clamps, adhesive or vulcanizing,so that the corrugated web will expand and contract with correspondingmovements of the master seal and shoe ring sections.

As seen in FIG. 2, the upper portion 27a of the corrugated web overliesthe annular clearance 14, surrounding the floating roof, contiguous withthe corresponding portions of the master seal. Preferably, the inturnedportion 27a of the expansion joint web, adjacent the top of the shoering, is folded upon itself as at 27b, where it is clamped both to theedges of the respective master seal sections and to the adjacent area ofthe shoe ring by the channel iron clamps 19a and 1%. Its oppositeinturned edge is secured to the floating roof flange 13 by the samebolts 22 which clamp the corresponding edge of the master seal.

Thus, in the area of the overlapping ends of the shoe ring sections, acontinuous expansion joint seal is provided which extends from at ornear the bottom of the shoe ring, to a point at or near the top of theshoe ring and thence inwardly where it is connected to the floatingroof. This minimizes any leakage at these points and provides a free andeasy movement of the overlapping shoe ring ends under conditions ofexpansion and contraction.

While I have shown and described a corrugated sealing web for theexpansion joint, it is to be understood that in some instances, aflexible web without prefabricated corrugations may be feasible,provided the material of the web is such that upon expansion andcontraction of the shoe ring, the web would adapt itself to accommodatethe necessary expansion and contraction. Otherwise, the construction andinstallation of the web would be the same as that previously described.In other words, the web would extend continuously from a point adjacentthe 4 bottom of the shoe ring to a point adjacent the top of the shoering and then continue radially inwardly where it is connected to thefloating roof.

Conventional shoe rings are ordinarily provided at their upper and loweredges with inturned flanges, and, in most instances, the adjacent endsof the shoe ring sections abut and are provided with so-called expansionjoints. I have found that by eliminating any flanges at the top orbottom of the shoe ring and overlapping the adjacent longitudinal endsthereof, a considerably improved performance is obtained. The previousinturned flanges, particularly at the top, had the effect of trappingrain and permitting it to leak in behind the shoe ring, a problem whichthe unfianged shoe avoids. Furthermore, the elimination of flanges tendsto improve the flexibility of the shoe ring and facilitates itsadjustability in expansion and contraction.

Ordinarily, suitable hangers are provided for connecting the floatingroof to the shoe ring, including means for urging the shoe ringoutwardly into close engagement with the inner wall of the tank. Whileany conventional means may be employed for this purpose, FIG. 5illustrates one form which has been found to be effective with thepresent invention. Here, it will be seen that a bar 31 is pivotallyconnected to the inner face of the shoe ring as at 32 and to thefloating roof as at 33. The upper end of a curved bar 34 is pivoted tothe floating roof wall at 35, and its opposite end, which is directedinwardly beneath the floating roof, is provided with a weight 36. Thus,the effect of the weight is to urge the curved bar 34 into contact withthe shoe ring for pushing it radially outwardly into contact with thetank wall. It will be understood that a series of these hangers areappropriately spaced around the floating roof.

From the foregoing, it is believed that the invention may be readilyunderstood by those skilled in the art without further description, itbeing borne in mind that numerous changes may be made in the detailsdisclosed without departing from the spirit of the invention as setforth in the following claims.

I claim:

1. In a cylindrical fluid storage tank having a floating roof, aperipheral sealing assembly therebetween, comprising an annular multiplesection shoe ring in slidable surface contact with the inner face of theshell of said tank with the longitudinal extremities of the sections ofthe ring in slidably adjustable, overlapping engagement, a multiplesection master seal secured along one edge to the inner surface of theupper portion of said shoe ring, with its opposite edge directedinwardly toward and secured to said floating roof, the annularextremities of the sections of said master seal, including its inwardlydirected portion, terminating in spaced relation adjacent the adjustableends of said shoe ring, a continuous expansion joint seal including aflexible sealing web bridging the spaced ends of said master seal, andthe overlapping extremities of said shoe ring extending substantiallyfrom the bottom to the top edge of said shoe ring, with its up perportion inturned to meet said floating roof, means for connecting theinturned portion of said expansion joint web to said floating roof,means for connecting the side edges of said expansion joint web to theadjacent spaced ends of the master seal, and means for securing therespective spaced ends of said master seal and corresponding side edgesof said expansion joint web to said shoe ring, at points adjacentopposite adjustable ends of the latter.

2. A sealing assembly as claimed in claim 1, wherein a verticalcross-section through said shoe ring at any point lies in anuninterrupted vertical plane from edge to edge.

3. A sealing assembly as claimed in claim 1, wherein saidshoe ring isformed of a plurality of arcuate sections, adjacent extremities ofrespective sections being arranged in overlapping relation, andexpansion joint seals being provided adjacent the overlappingextremities of said sections.

4. A sealing assembly as claimed in claim 3, wherein said master seal isformed in sections corresponding to those of said shoe ring.

5. A sealing assembly as claimed in claim 1, wherein said expansionjoint seal comprises a corrugated web to facilitate expansion andcontraction.

6. A sealing assembly as claimed in claim 5, wherein respective sideedges of said expansion joint web adjacent the overlapping ends of saidshoe ring are secured directly to the latter.

7. A sealing assembly as claimed in claim 1, including means fordirectionally controlling and limiting the movement of the overlappingends of said shoe ring upon expansion and contraction of the latter.

8. A sealing assembly a claimed in claim 7, wherein UNITED STATESPATENTS 1,574,013 2/1926 Wiggins 220-26 1,931,551 10/1933 Larson 220-261,979,657 11/1934 Wiggins 22026 FOREIGN PATENTS 478,044 10/ 1951 Canada.

THERON E. CONDON, Primary Examiner.

I. R. GARRETT, Assistant Examiner.

